High-yield reward checking accounts that pay the top rates on large balances are rare these days. If you want a balance cap above $25K, it's hard to find, and if you do find one, you may not be happy with the interest rate. Two good examples of this are the reward checking accounts that are available nationwide. The Bank of Fayetteville's reward checking account has a 2.75% APY for balances up to $50K as of 11/29/2010. North Country Savings Bank also has a $50K balance cap, but its rate is only 2.00% APY as of 11/29/2010.
If you want just one reward checking account for a $50K balance, you may actually do better with a reward checking account with a $25K cap and a higher second tier rate. For example, Liberty Bank has a reward checking account with a 3.01% APY for balances up to $25K and 1.01% APY for portion of the balance over $25K (as of 11/29/2010). For a $50K balance, you'll earn a little more in this account than in North Country Savings Bank. Unfortunately, second tier caps have also been falling with the top tier rates. The 1.01% rate used to be common for second tier rates, but most reward checking accounts now have second tier rates under 1.00%.
You may be able to find better deals at banks and credit unions local to you. There are several banks and credit unions offering 3.00% and above with balance caps of $50K. These are only local deals. You can find these by using our reward checking account table. If the table default doesn't show the accounts in your state, you can select your state by selecting the "Filter Accounts" button. Note, in many cases the bank or credit union may be limited to certain parts of the state or be limited by certain employer groups. For example, Market USA Federal Credit Union has a great reward checking deal with a 4.00% APY on balances up to $50K. Unfortunately, membership is limited primarily to select employee groups.